Accepted by W. Sterrer: 14 Nov. 2013; published: 9 Dec. 2013 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2013 Magnolia Press Zootaxa 3745 (5): 569–578 www.mapress.com/zootaxa/ Article 569 http://dx.doi.org/10.11646/zootaxa.3745.5.5 http://zoobank.org/urn:lsid:zoobank.org:pub:D86E6EEE-5B0B-4E7A-9F90-63DA2A76E9F1 Two new species of Gieysztoria (Platyhelminthes, Rhabdocoela, Dalyelliidae) from a Freshwater Artificial Lake in Shenzhen, China YAN-HONG LU 1 , CHENG-CHEN WU 2 , XIAO-JIE XIA 1 & AN-TAI WANG 1,3 1 College of Life Science, Shenzhen University, Shenzhen 518060, China 2 Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, China 3 Corresponding author. E-mail: wang118@szu.edu.cn Abstract Two new species of the “Aequales” of genus Gieysztoria were collected and described from an artificial lake on the Shen- zhen University campus. Gieysztoria bimaculata n. sp., is distinguished based on two groups clavate pigmentations dor- sally between the pharynx and intestine, and has a sclerotic stylet comprising a proximal girdle with 40–46 distal dagger- shape spines, thus has the maximum number of spines within “Aequales” group. Gieysztoria guangdongensis n. sp. has a sclerotic stylet with a proximal girdle and 18 distal blade-shaped spines. Comparison with similar species based mainly on stylet morphology suggests that Gieysztoria bimaculata n. sp. and Gieysztoria guangdongensis n. sp. are apparently different from the known species of Gieysztoria in this moment. In addition, the stability of the amount of distal spines of “Aequales” species is briefly discussed. Key words: turbellarian, new species, Rhabdocoela, Dalyelliidae, Gieysztoria; taxonomy Introduction Gieysztoria Ruebush and Hayes, 1939, the most species-rich genus within Dalyelliidae Graff, 1908, is mostly limnic with just a few species present in brackish or marine environments (Van Steenkiste et al. 2012). With approximately 90 species described in the freshwater environment worldwide, the genus Gieysztoria Ruebush and Hayes, 1939, is traditionally classified into two groups—“Aequales” and “Inaequales” (Tyler et al. 2012; Van Steenkiste et al. 2012; Lai 2013). “Aequales” contains species with a stylet composed of a proximal girdle and distal spines of similar length and shape. “Inaequales”, contains species with a stylet composed of different length and shape. “Inaequales” is further subdivided into 3 groups: “Fenestratae”; “Radiatae”; and “Aberrantes”(Luther 1955 ; Damborenea et al. 2005; Van Steenkiste et al. 2012). Recently, “Falcatae” has been established as a new subgroup within “Inaequales”, sharing a large robust falcate stylet spine as a common feature (Van Steenkiste et al. 2012). As to biogeography, China stretches over the Oriental and Palearctic realms. Since 21 st Century, 12 species of Rhabdocoela (Meixner, 1925) have been recorded and described in the Oriental realm within China’s national land (Wang & Sun 2011; Wang 2004; Wang & Deng 2006; Wang & Wu 2005a, 2005b, 2008; Zhang et al. 2011; Lai et al. 2013), among which there are four species of Gieysztoria: G. shenzhensis (Wang & Wu 2005b); G . pulchra (Wang & Deng 2006) ; G . macrovariata 9 –spinosa (Luther 1955; Wang & Deng 2006); and G . wuyishanensis (Lai et al. 2013). G. shenzhensis belongs to the “Radiatae”; G . pulchra and G . macrovariata 9 –spinosa belong to “Aberrantes”. Species of “Fenestrate” are currently unknown in China. One new species of “Falcatae” is found in the south of China (Lai et al. 2013). In this contribution, we described two new species of “Aequales” collected from the artificial lake in Shenzhen University campus. The structure of their stylet is unique among the “Aequales” group and this report constitutes the first description of species of the “Aequales” group of Gieysztoria in China.